The present invention relates generally to an apparatus configured to assist in glazing ceramic, stoneware, and porcelain articles and vessels. In particular, the present invention relates to an apparatus that achieves blemish-free glazing of ceramic articles by providing a clamp assembly that secures the ceramic article during the dipping and drying portions of the glazing process.
Glaze is a layer or coating of a vitreous substance which has been fused to a ceramic object through firing. Glaze can serve to color, decorate, strengthen and/or waterproof an item. Ceramic glazes generally contain silica to form glass, in combination with a mixture of metal oxides and other additives to provide color and proper flow characteristics to the glaze.
Liquid glazes, in the form of suspensions of various powdered minerals and metal oxides, may be applied by dipping the pieces directly into the glaze. Once dipped, the liquid glaze is allowed to dry before the firing process. During the firing process, the dried glaze melts to form a desired coating on the clay body.
An important aspect of some glazing processes is to ensure that the glaze is applied evenly to all of the decorative surfaces of the ceramic object. However, liquid glazes require that the ceramic piece be held by the artisan during the dipping process. In some instances, an artisan will hold the ceramic object with their fingers while dipping the piece into the glaze. In other instances, an artisan will use a pair of tongs to grip the ceramic object for dipping.
For both of these situations, the surface which is contacted or held either received no glaze, or receives some glaze during the firing process as the glaze is liquefied and flows onto the uncoated surfaces. Thus, the final glaze coating on the ceramic object contains blemishes where the object was held during the dipping process.
Furthermore, in some instances the artisan will dip the upper have of the vessel by holding the piece by the lower half. Once the liquid glaze has set, the artisan suspends the piece from the inside and dips the lower half of the vessel up to the line established by the first dip. The conjuncture of the two separate dips results invariably in a thickened layer of glaze.
In some instances, a potter will design a vessel around the conjuncture line to allow for the thickened band of glaze. For example, a potter may put a line on the shoulder of the piece to serve as a physical depth marker for dipping. The potter anticipates that the band of thickened glaze created on the surface of the piece will hide the line or depth marker created by the potter when the vessel is dipped using this method. As a result, the fired piece appears to be free of blemishes.
A further method of glazing available to artisans or potters is that of spraying. The interior of the ceramic vessel is first coated with a layer of glaze which is allowed to dry. The vessel is then placed in a spray booth on a rotating surface. Glaze is pneumatically pressurized and sprayed onto the vessel in a slow consistent manner leaving a mostly even coating of glaze on the surface of the piece. Hasty spraying can leave drips, and the artisan has no fast and sure way to understand how thick the glaze has been applied over the surface of the piece. The glaze will generally be thicker in the broader surfaces of the ceramic vessel which are exposed to increase spraying. The cost of this process is exorbitant due to the required materials and equipment. Furthermore, the booths, spraying apparatuses, and air filtration systems for the booths require extensive maintenance and cleaning, thereby further complicating the process.
While methods exist for applying liquid glaze to a vessel, challenges still remain. Accordingly, there is a need for an improved apparatus and method for applying liquid glaze to a ceramic object to obtain a blemish-free glaze coating. Such an apparatus and method is disclosed herein.